Disturbed Distributor

91 Sonoma 4.3. Distributor was left unmarked then pulled and crankshaft had been turned prior to re-install. Under hood info reads Set timing to 0 BTC. So, how do you find BTC? What procedure do you follow to re-install this disturbed distrib?

o.k. remember crank turns twice of camshaft,so you will have 2 times on balancer marks to 1 actual revolution.hence,4 stroke motor,suck,squeeze,pop,fart. 4 stroke! without removing valvecover disconnect coil wire,just turn over motor with starter with 1 plug removed,have finger in plug hole,feel for the stronger pressure,comp.stroke is more pronounced than exhaust stroke,this all happens right before the mark on balancer comes to timing mark on motor,do short bursts on starter,so if you pass a little,just turn back by hand,when setting dist.point rotor at no 1 cyl.(drivers side front)you have to hold the dist. by hand with slight pressure while cranking motor again to line up oil pump drive,once it sets down doublecheck timing again,install hold down lightly to turn to time,if i missed anything,ill be here

Awesome. One more thing to clear up for me. Pointing rotor toward #1 cyl (between cap terminal 2 and 1?) sets up to fire #1 just before TDC? I re-installed the distrib firstly by finding TDC but I set the rotor pointing directly at
distrib cap Term #1, no good. When I cranked to find TDC, near the timing mark on balancer air escaped spark port #1...this could be the exhaust stroke? Would it still run, all be it badly, if timing was set up on the wrong stroke?

do it again,you will feel a stronger escape on compression stroke,if uncertain,crank again to make sure youre not on exhaust(fart)stroke,remember i mentioned to go a little counterclockwise when setting dist.the gear is curved(for lack of a correct term)do you understand that last step about the oil pump drive?cause the dist.will be high in its mount,so when it drops,sometimes you are a.t.d.c.

Thanks alot for the help. Im gonna get back at it soon. Prob after prob on this thing so far and a second experienced opinion is a load off. Im just burnt out on this electronically controled, 20 yr old nightmare. Thanks again Geo1.